【iOS开发系列】颜色渐变

//Transparent Gradient Layer
- (void) insertTransparentGradient {
UIColor *colorOne = [UIColor colorWithRed:(33/255.0)  green:(33/255.0)  blue:(33/255.0)  alpha:0.0];
UIColor *colorTwo = [UIColor colorWithRed:(33/255.0)  green:(33/255.0)  blue:(33/255.0)  alpha:1.0];
NSArray *colors = [NSArray arrayWithObjects:(id)colorOne.CGColor, colorTwo.CGColor, nil nil];
NSNumber *stopOne = [NSNumber numberWithFloat:0.0];
NSNumber *stopTwo = [NSNumber numberWithFloat:1.0];
NSArray *locations = [NSArray arrayWithObjects:stopOne, stopTwo, nil nil];

//crate gradient layer
CAGradientLayer *headerLayer = [CAGradientLayer layer];

headerLayer.colors = colors;
headerLayer.locations = locations;
headerLayer.frame = self.bounds;

[self.layer insertSublayer:headerLayer atIndex:0];
}

//color gradient layer
- (void) insertColorGradient {

UIColor *colorOne = [UIColor colorWithRed:(255/255.0) green:(255/255.0) blue:(255/255.0) alpha:1.0];
UIColor *colorTwo = [UIColor colorWithRed:(33/255.0)  green:(33/255.0)  blue:(33/255.0)  alpha:1.0];

NSArray *colors = [NSArray arrayWithObjects:(id)colorOne.CGColor, colorTwo.CGColor, nil nil];
NSNumber *stopOne = [NSNumber numberWithFloat:0.0];
NSNumber *stopTwo = [NSNumber numberWithFloat:1.0];

NSArray *locations = [NSArray arrayWithObjects:stopOne, stopTwo, nil nil];
CAGradientLayer *headerLayer = [CAGradientLayer layer];
headerLayer.colors = colors;
headerLayer.locations = locations;
headerLayer.frame = self.bounds;

[self.layer insertSublayer:headerLayer above:0];

}